The present invention relates to a circuit and a musical instrument, equipped with an amplifying unit.
Apparatuses being equipped with a capacitor for supplementing the operating power thereof have been proposed. JP-T-2004-503199 discloses an apparatus equipped with a capacitor that is charged, for example, by the power supplied via a USB (universal serial bus) power supply line, the supply power of which is limited.
However, in the case that an apparatus is equipped with an amplifying unit, a signal processing unit for processing the signal to be input to the amplifying unit is provided together with the amplifying unit, a battery is used as the power source for supplying the power source voltage of the amplifying unit and is also used as the power source for supplying the power source voltage of the signal processing unit in some cases. In such a case, the battery supplies the voltage of the battery as the power source voltage for both the amplifying unit whose power consumption may fluctuate significantly and the signal processing unit whose power consumption fluctuates slightly. Since the power consumption of the amplifying unit fluctuates due to the amplification operation thereof, it is conceivable that the voltage of the battery may fluctuate. As a result, the fluctuations of the battery voltage directly lead to the fluctuations of the power voltage of the signal processing unit. The operation of the signal processing unit becomes unstable due to the fluctuations of the power source voltage and may cause the stop of the operation in some cases. Although JP-T-2004-503199 describes power supply to, for example, peripheral devices, but does not describe that there are differences in the power consumption fluctuations of the respective peripheral devices due to their operations, and does not describe any specific methods for distributing power between a device having large power consumption fluctuations and a device having small power consumption fluctuations.